John was born on February 28, 1999. It was a Sunday. February of that year had only 28 days, and the year had exactly 365 days. His brother Jack was born on the same day of the year 2000. February of the year 2000 had 29 days. On which day was Jack born?

Options

A. Monday
B. Tuesday
C. Friday
D. Saturday

Answer

To determine the day of the week on which Jack was born (February 28, 2000), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Birthdays**:
- John was born on February 28, 1999, which was a Sunday.
- Jack was born on February 28, 2000.

2. **Determine the Year Types**:
- The year 1999 is not a leap year (it has 365 days).
- The year 2000 is a leap year (it has 366 days).

3. **Calculate the Days Between the Two Birthdays**:
- From February 28, 1999, to February 28, 2000, there is exactly 365 days (since 2000 is a leap year, February has 29 days).

4. **Convert Days to Weeks**:
- To find out how many weeks are in 365 days, we divide by 7 (the number of days in a week):
\[ 365 \div 7 = 52 \text{ weeks} \text{ with a remainder of } 1 \text{ day} \]

5. **Determine the Day of the Week for Jack's Birthday**:
- Since John was born on a Sunday, after 52 weeks (which brings us back to Sunday), we have 1 extra day.
- Therefore, if we add 1 day to Sunday, we get Monday.

6. **Conclusion**:
- Jack was born on February 28, 2000, which was a **Monday**.

### Final Answer:
Jack was born on a **Monday**.